Photographic objective for picturetaking or projection



SEARCH ROOM March 13, 1962 J. BERGER PHOTOGRAPHIC OBJECTIVE FOR PICTURE TAKING OR PROJECTION Filed Oct. 31, 1960 United States Patent 3,024,697 PHOTOGRAPHIC OBJECTIVE FOR PICTURE- TAKING 0R PROJECTION Johannes Berger, Heidenheim (Brenz), Wurttemberg, Germany, assignor to Carl Zeiss, Heidenheim (Brenz), Wurttemberg, Germany Filed Oct. 31, 1960, Ser. No. 66,353 Claims priority, application Germany Nov. 10, 1959 1 Claim. (Cl. 88-57) The present invention concerns photographic objectives for picture-taking or for projection particularly objectives suitable for sub-standard film cameras or projectors. They consist of five lenses. The first lens-in objectives used for picture-taking the said lens is the lens turned towards the object and in objectives used for projection it is the lens turned towards the screen surface-is an asymmetrical collective lens which turns its surface of shallower curvature towards the second lens which second lens is also an asymmetrical collective lens which turns its surface of shallower curvature towards the third lens which third lens is an asymmetrical dispersive lens which turns its surface of deeper curvature towards the fourth lens which fourth lens is also an asymmetrical dispersive lens which turns its surface of deeper curvature towards the fifth lens which fifth lens is a biconvex collective lens.

The investigations on -which the invention is based have shown that in objectives of the said design a correction suitable for the purpose indicated can be attained for angular fields of approximately :12 and for an aperture ratio of f:1.4 if the following conditions are simultaneously satisfied:

wherein there are designated By r the radii,

By d the axial separations,

By B the overall length, and

By the focal length of the objective.

With a view to the correction of the coma it is advan- 3,024,697 Patented Mar. 13, 1962 ice tageous to cement the second and the third lens together.

A preferred form of the objective is illustrated in the accompanying FIGURE of the drawing.

In the following table there are indicated the design data for an objective according to the invention with a relative aperture of 1:1.4 and with an angular field of $122 Therein there are designated:

By L the lenses,

By r the radii,

By d the axial separations,

By ri the refractive indices,

By y the Abbe numbers for the d-line of the Helium spectrum,

By s the back focal length,

By 1371/ r the surface refractive powers, and

By f the focal length of the objective.

Within the scope of the present invention there are included also objectives with design data approximating so closely to the values taken from the appended table that each surface refractive power (An/r) departs by a maximum of i0.30-1/f and each axial separation departs by a maximum of i0.03-f from the corresponding value given in the table.

I claim:

A photographic objective for picture-taking and projection consisting of five lenses wherein the first lens is an asymmetrical collective lens which turns its surface of weaker curvature towards the second lens, which second lem is also an asymmetrical collective lens which turns its surface of weaker curvature towards the third lens, which third lens is an asymmetrical dispersive lens which turns its surface of stronger curvature towards the fourth lens, which fourth lens is also an asymmetrical dispersive lens which turns its surface of stronger curvature towards the fifth lens, which fifth lens is a biconvex (a) 0.l-B d +d +d +d 0.30-B

(b) 0.70-f B 1.40-f

(c) 1.00-r r 3.5O-r

(d) 1.00-r r 3.00-r

(e) 0.35-r r 0.70-r,

(f) 0.80-r r 1.80-r,

(8) O.40-d d,

wherein there are designated By r the radii,

By d the axial separations,

By B the overall length, and

By f the focal length of the objective and furthermore, characterized in that its design data approximate so closely to the values taken from the appended table that none of the surface refractive powers (An/ r dilfers 25 2,502,509

absolutely by more than 0.30-1/f and none of the axial separations '(d) difiers absolutely by more than 0.03 -f from the corresponding value given in the table:

Lenses Radii Axial sep- 12 v An/r arations r =+1.l3542-f +0. 5405 Lr d|=0.1710-f 1. 02041 60.29

dz=0.0032-f n=+0.50s92-/ +1. 2533/] Ln d3=0.2072-1 1. 71300 53.89

d4=0.0000-f r 0.0000/f L111.--" d =0.0583-] 1. 63980 34. 00

rt=+o.00s9s- -0. 0003 1 d6=0.0745-f r1= 0.62473-f -0.125s/! Lw..-.. d1=0.1300- 1. 70410 20.10

TB=+0.34380-f -2. 2824/] a=0.1243- n=+0.67l26-f +1.1084/f Lv d9=0.1813'f 1. 74400 44.90

n0= 0.80934-] -0. 9193 NOTE.8'=O.4030']'.

References Cited in the file of this patent UNITED STATES PATENTS Cook Apr. 4, 1950 2,600,208 Cook June 10, 1952 

